Preparation And Application Of ETS-4 And LSX Molecular Seives

In recent years, with the rapid development of industry, environmental protection and energy efficiency problems are becoming more and more important. For the present situation of industrial progress, the government successively put forward some policies, including the sustainable development, construction of environmental friendly and resource-saving society. Recently supporting the policy of the government, numerous scientific research institutions at various levels have proceeded with exploration and research in energy saving, environmental protection and efficient utilization of resources arid so on, and suggested a large amount of imagines to realize environmental friendly and resource-saving society. With increasing scale of industry, it will bring enormous economic profits and important to lower down producing cost and develop the process of adsorption-and-desorption that saves more energy resources.The adsorbent, the core of the adsorption separation process, has become the research hotspot. However, researches are mainly concentrated on the synthesis of new adsorbent and the improvement in backward adsorbent synthesis process. This paper is investigated in two aspects.1. Sr-ETS-4 molecular sieve which has high thermal stability and excellent performance for N2/CH4 separation is prepared by aqueous solution exchange method from Na-ETS-4 molecular sieve with poor thermal stability and unsatisfactory result for N2/CH4 separation. The XRD patterns show that some feature peaks of Sr-ETS-4 molecular sieve are more intensive than that of Na-ETS-4 molecular sieve, but there is almost no change in the morphology after ion exchange. Concentration of exchanging liquid, exchanging temperature, pH value and exchanging time are main influencing factors of ion exchange. The optimal process conditions of preparing Sr-ETS-4 molecular sieve follow:SrCl2 solution concentration is 25%, exchanging temperature is 75 ℃, aqueous solution exchanging time is 90 minute and pH value is 7.5. After the temperature of exchanging solution going down 60-70 ℃, Sr-ETS-4 molecular sieve is filtered, washed and dried.2. Li-LSX molecular sieve are prepared by two-step aqueous solution exchange method, which Na-LSX molecular sieve exchanged of NH4-LSX molecular sieve, and then exchanged with the solution LiOH. Its preparation method is replaced aqueous solution exchange method with microwave radiation ion-exchange method. In this paper, NH4-LSX molecular sieve with one-step aqueous solution exchange method is research emphasis. On the basis of above experiments, microwave radiation ion-exchange mechanism is investigated by interrupted experiment. The optimal conditions of preparation for NH4-LSX molecular sieve are as follows:concentration of exchanging liquid is 1mol/L, exchanging temperature is 70 ℃, microwave radiation power is 80W, microwave radiation ion-exchanging time is 15 minute and it needs 2 sequence ion-exchanging. In order to increase exchanging degree, microwave radiation power, exchanging temperature, exchanging time and concentration of the exchanging liquid. However, when increasing the frequency of ion-exchanging in aqueous solution exchange method, the morphology of LSX molecular sieve has changed greatly. Comparing with the microwave radiation ion-exchange, the aqueous solution exchange method takes more exchanging time. It can be concluded that microwave exchange mechanism pertain to liquid film diffusion by employing the interrupt experiment method.